The present invention is directed to a drill or chisel bit having an axially extending body with an axially extending insertion end for placement into a chuck on a drive unit. The insertion end has axially extending grooves for providing rotationally locked connection with and axially retention in the chuck.
Tool bits of the above-mentioned type are known, such as in DE-PS 2 551 125 and are used in particular for work in rock. When the tool bits are inserted into a chuck of a drive unit, stationary or radially displaceable locking elements engage in a positive locking manner into the axially extending grooves. The locking elements transmit torque to the tool bit and, at the same time, prevent the tool bit from being displaced out of the chuck.
In actual operation, the drill or chisel bits move in the axial direction in the drive unit chuck. Because of this axially directed movement, there is relatively great wear in the grooves as well as on the locking elements engaged in the grooves. Moreover, the axially extending grooves tend to accumulate dirt and can result in malfunction of the chuck, so that the tool bit can no longer be satisfactorily locked within and may be pushed out of the chuck during operation.